Louis Keith Collier (born August 21, 1973) is an American former professional baseball utility player.

He played in Major League Baseball (MLB) for the Pittsburgh Pirates, Milwaukee Brewers, Montreal Expos, Boston Red Sox, and Philadelphia Phillies.

He reached the Majors in 1997 with the Pittsburgh Pirates, spending two years with them before moving to the Milwaukee Brewers (1999-2001), Montreal Expos (2002), Boston Red Sox (2003) and Philadelphia Phillies (2004).

In 1998 with Pittsburgh, he posted career-highs in games played (110), hits (82), runs (30), RBI (34), doubles (13) and triples (6).

In 2007, he was invited by the Philadelphia Phillies to spring training after spending two seasons with the LG Twins and Hanwha Eagles in Korea Baseball Organization.